/*
自己选择的路 ,跪着也要走完。朋友们 , 虽然这个世界日益浮躁起来,只
要能够为了当时纯粹的梦想和感动坚持努力下去 , 不管其它人怎么样,我
们也能够保持自己的本色走下去。
To the world , you will be a person , but to a person , you
will be the world .                               ——AKPower
*/
//作者:AKPower
//算法:
#include <iostream>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <vector>
#include <map>
#include <queue>
#include <cstdio>
#include <string>
#include <stack>
#include <set>
#define IOS ios::sync_with_stdio(false), cin.tie(0)
using namespace std;
typedef long long ll;
const ll maxn = 1e6 + 10;
ll a[maxn], b[maxn], n, k, T;
map<ll, ll> mp;

int main()
{
    IOS;
    cin >> T;
    while (T--)
    {
        mp.clear();
        cin >> n >> k;
        for (ll i = 1; i <= n; i++)
        {
            cin >> a[i];
            b[i] = (b[i - 1] + a[i]) % k;
        }
        // for (ll i = 1; i <= n; i++)
        // {
        //     cout << b[i] << " ";
        // }
        // cout << endl;
        ll ans = -1;
        for (ll i = 1; i <= n; i++)
        {
            if (mp.find(b[i]) != mp.end())
            {
                ans = max(ans, i - mp[b[i]]);
                continue;
            }
            if (b[i] == 0)
            {
                ans = i;
                continue;
            }
            mp[b[i]] = i;
        }
        cout << ans << endl;
    }
    getchar();
    getchar();
    return 0;
}
